spot weld newbie

[Robotstar5]

Also is there any way to increase the size of the weld?

It's difficult with a fixed power welder to vary spot size as increasing the time can produce too much heat and the tips will try to meet .

Right, trying to remember resistance weld theory An industrial welder will have a weld controller that turns the power on & off very quickly, by varying the time triacs are turned on for each cycle of the mains input. They would be turned on for a short while so reducing the power to the transformer which would allow the heat to build up slower giving a larger diameter weld.

Example of a weld controller (quite an old one) - link

If you want a better explanation I will need to dig my technical books out!

 

[David 123]

Thanks for the advice. A weld controller is not an option for financial reasons. Just surprised that electrodes as thick as my thumb produce a 3mm nugget. Guess I should have asked on here before buying a welder. Fools rush in etc.
Thanks
David